Snapper Hi-Vac Engine Issue

[fritz1255]

I have a 90's vintage Snapper Hi-Vac self propelled walk behind mower. When the original Tecumseh engine died, I replaced it with a Briggs & Stratton 190cc 8.5 foot pound torque engine. All went well for three years kuntil I replaced the drive belts. After that, it made noises like a severe spark knock. The flywheel shear pin sheared and the bushing that attaches the blade to the crankshaft actually broke. Replaced the shear pin and bushing, same result. It almost sounds to me like the ignition timing is way off and is stopping the engine mid-stroke, but is this even possible with a magneto ignition system? I have checked the deck and have not found any blade obstruction, nor are there any marks on the blade. Any suggestions?

 

[gvanek]

Hard to imagine that heavy blade adapter breaking without hitting something really hard.

So, it will start up, without any unusually difficulty, and run?...but sounds horrible?

 

[fritz1255]

Yes, starts and runs. Almost sounds like a "spun" journal bearing. Is this even possible with a lawnmower?

 

[gvanek]

If the "timing was out", it could only be due to the flywheel being out of place, but you said you repaired the broken keyway, so that can't be it...and you'd have some considerable "pull back" when trying to hand crank.

Forgive me if you've already tried this:

I'd remove the drive belt to attempt to isolate the source of the noise. If no noise when belt removed, then problem is in the drive mechanism. We can move on from that point.

If noise remains, there's something nasty inside (wollowed out journal, broken oil slinger,...). A bent crankshaft is not out of the question. Not sure it's worth tearing the engine apart and replacing parts when you can buy a replacement for about $200.

 

[fritz1255]

Ok I'll try that. You are correct about the price, not worth digging into the engine. I recently had to replace my riding mower with a zero turn, so fixing this one does not have the urgency it would have a few months ago.

 

[atomic67]

I am working on a 95 P21550 with the Kawasaki fc150 engine. Ignition coils are expensive, but I watched a video and a Honda GX160 coil was used. Is this possible?